NFS: Fix following referral mount points with different security

I create a new proc_lookup_mountpoint() to use when submounting an NFS
v4 share.  This function returns an rpc_clnt to use for performing an
fs_locations() call on a referral's mountpoint.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

5 files changed, 72 insertions, 26 deletions

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 45966d953169..49c09b4a535a 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -186,10 +186,10 @@ static inline void nfs_fs_proc_exit(void)
 
 /* nfs4namespace.c */
 #ifdef CONFIG_NFS_V4
-extern struct vfsmount *nfs_do_refmount(struct dentry *dentry);
+extern struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry);
 #else
 static inline
-struct vfsmount *nfs_do_refmount(struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
 {
         return ERR_PTR(-ENOENT);
 }
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 1807866bb3ab..b9a593d056b3 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -200,6 +200,22 @@ out_shutdown:
 out:
         return err;
 }
+
+static struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir,
+                                              struct qstr *name,
+                                              struct nfs_fh *fh,
+                                              struct nfs_fattr *fattr)
+{
+        int err;
+
+        if (NFS_PROTO(dir)->version == 4)
+                return nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
+
+        err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
+        if (err)
+                return ERR_PTR(err);
+        return rpc_clone_client(NFS_SERVER(dir)->client);
+}
 #else /* CONFIG_NFS_V4 */
 static inline int nfs_lookup_with_sec(struct nfs_server *server,
                                       struct dentry *parent, struct dentry *dentry,
@@ -209,6 +225,17 @@ static inline int nfs_lookup_with_sec(struct nfs_server *server,
 {
         return -EPERM;
 }
+
+static inline struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir,
+                                                     struct qstr *name,
+                                                     struct nfs_fh *fh,
+                                                     struct nfs_fattr *fattr)
+{
+        int err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
+        if (err)
+                return ERR_PTR(err);
+        return rpc_clone_client(NFS_SERVER(dir)->client);
+}
 #endif /* CONFIG_NFS_V4 */
 
 /*
@@ -226,11 +253,10 @@ static inline int nfs_lookup_with_sec(struct nfs_server *server,
 struct vfsmount *nfs_d_automount(struct path *path)
 {
         struct vfsmount *mnt;
-        struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
         struct dentry *parent;
         struct nfs_fh *fh = NULL;
         struct nfs_fattr *fattr = NULL;
-        int err;
+        struct rpc_clnt *client;
         rpc_authflavor_t flavor = RPC_AUTH_UNIX;
 
         dprintk("--> nfs_d_automount()\n");
@@ -249,21 +275,19 @@ struct vfsmount *nfs_d_automount(struct path *path)
 
         /* Look it up again to get its attributes */
         parent = dget_parent(path->dentry);
-        err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode,
-                                                  &path->dentry->d_name,
-                                                  fh, fattr);
-        if (err == -EPERM && NFS_PROTO(parent->d_inode)->secinfo != NULL)
-                err = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr, &flavor);
+        client = nfs_lookup_mountpoint(parent->d_inode, &path->dentry->d_name, fh, fattr);
         dput(parent);
-        if (err != 0) {
-                mnt = ERR_PTR(err);
+        if (IS_ERR(client)) {
+                mnt = ERR_CAST(client);
                 goto out;
         }
 
         if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
-                mnt = nfs_do_refmount(path->dentry);
+                mnt = nfs_do_refmount(client, path->dentry);
         else
                 mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
+        rpc_shutdown_client(client);
+
         if (IS_ERR(mnt))
                 goto out;
 
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index c82c2cda3dfd..8d75021020b3 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -216,8 +216,10 @@ extern int nfs4_init_clientid(struct nfs_client *, struct rpc_cred *);
 extern int nfs41_init_clientid(struct nfs_client *, struct rpc_cred *);
 extern int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait, bool roc);
 extern int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle);
-extern int nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
-                struct nfs4_fs_locations *fs_locations, struct page *page);
+extern int nfs4_proc_fs_locations(struct rpc_clnt *, struct inode *, const struct qstr *,
+                                  struct nfs4_fs_locations *, struct page *);
+extern struct rpc_clnt *nfs4_proc_lookup_mountpoint(struct inode *, struct qstr *,
+                            struct nfs_fh *, struct nfs_fattr *);
 extern int nfs4_proc_secinfo(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);
 extern int nfs4_release_lockowner(struct nfs4_lock_state *);
 extern const struct xattr_handler *nfs4_xattr_handlers[];
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 9f8681bf90de..a7f3dedc4ec7 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -300,7 +300,7 @@ out:
  * @dentry - dentry of referral
  *
  */
-struct vfsmount *nfs_do_refmount(struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
 {
         struct vfsmount *mnt = ERR_PTR(-ENOMEM);
         struct dentry *parent;
@@ -326,7 +326,7 @@ struct vfsmount *nfs_do_refmount(struct dentry *dentry)
         dprintk("%s: getting locations for %s/%s\n",
                 __func__, parent->d_name.name, dentry->d_name.name);
 
-        err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
+        err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
         dput(parent);
         if (err != 0 ||
             fs_locations->nlocations <= 0 ||
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3d92fe6be780..75eb883ed4ce 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2377,8 +2377,9 @@ static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
  * Note that we'll actually follow the referral later when
  * we detect fsid mismatch in inode revalidation
  */
-static int nfs4_get_referral(struct inode *dir, const struct qstr *name,
-                             struct nfs_fattr *fattr, struct nfs_fh *fhandle)
+static int nfs4_get_referral(struct rpc_clnt *client, struct inode *dir,
+                             const struct qstr *name, struct nfs_fattr *fattr,
+                             struct nfs_fh *fhandle)
 {
         int status = -ENOMEM;
         struct page *page = NULL;
@@ -2391,7 +2392,7 @@ static int nfs4_get_referral(struct inode *dir, const struct qstr *name,
         if (locations == NULL)
                 goto out;
 
-        status = nfs4_proc_fs_locations(dir, name, locations, page);
+        status = nfs4_proc_fs_locations(client, dir, name, locations, page);
         if (status != 0)
                 goto out;
         /* Make sure server returned a different fsid for the referral */
@@ -2550,7 +2551,7 @@ static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
                         err = -ENOENT;
                         goto out;
                 case -NFS4ERR_MOVED:
-                        err = nfs4_get_referral(dir, name, fattr, fhandle);
+                        err = nfs4_get_referral(client, dir, name, fattr, fhandle);
                         goto out;
                 case -NFS4ERR_WRONGSEC:
                         err = -EPERM;
@@ -2591,6 +2592,21 @@ static int nfs4_proc_lookup(struct rpc_clnt *clnt, struct inode *dir, struct qst
         return status;
 }
 
+struct rpc_clnt *
+nfs4_proc_lookup_mountpoint(struct inode *dir, struct qstr *name,
+                            struct nfs_fh *fhandle, struct nfs_fattr *fattr)
+{
+        int status;
+        struct rpc_clnt *client = rpc_clone_client(NFS_CLIENT(dir));
+
+        status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr);
+        if (status < 0) {
+                rpc_shutdown_client(client);
+                return ERR_PTR(status);
+        }
+        return client;
+}
+
 static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
 {
         struct nfs_server *server = NFS_SERVER(inode);
@@ -4951,8 +4967,10 @@ static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr)
         fattr->nlink = 2;
 }
 
-static int _nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
-                struct nfs4_fs_locations *fs_locations, struct page *page)
+static int _nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
+                                   const struct qstr *name,
+                                   struct nfs4_fs_locations *fs_locations,
+                                   struct page *page)
 {
         struct nfs_server *server = NFS_SERVER(dir);
         u32 bitmask[2] = {
@@ -4986,19 +5004,21 @@ static int _nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
         nfs_fattr_init(&fs_locations->fattr);
         fs_locations->server = server;
         fs_locations->nlocations = 0;
-        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
+        status = nfs4_call_sync(client, server, &msg, &args.seq_args, &res.seq_res, 0);
         dprintk("%s: returned status = %d\n", __func__, status);
         return status;
 }
 
-int nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
-                struct nfs4_fs_locations *fs_locations, struct page *page)
+int nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
+                           const struct qstr *name,
+                           struct nfs4_fs_locations *fs_locations,
+                           struct page *page)
 {
         struct nfs4_exception exception = { };
         int err;
         do {
                 err = nfs4_handle_exception(NFS_SERVER(dir),
-                                _nfs4_proc_fs_locations(dir, name, fs_locations, page),
+                                _nfs4_proc_fs_locations(client, dir, name, fs_locations, page),
                                 &exception);
         } while (exception.retry);
         return err;